Self-adjusting open or closed-end ratchet wrench

ABSTRACT

A self-adjusting open or closed-end ratcheting wrench that accommodates a range of nut sizes comprises a wrench body with one fixed jaw, a single ratcheting pawl that moves in an arcuate manner so as to fit a range of nut sizes, an elastic actuator mechanism for biasing the pawl to its operating position, and a slide handle coupled to the actuator mechanism to permit installing around a nut. The motion of the pawl places it in the proper position and gives it the proper angular orientation to provide two drive positions for each face of a polygonal nut. In one drive position the nut is driven by three contacting surfaces, and in the other drive position the nut is driven by two contacting surfaces. These two drive positions provide ratcheting every 30* or 60* on a hexagonal nut. Multiple contact surfaces between the pawl and the jaw with which it mates provide high friction during the drive phase of operation but the inclination and curvature of the surfaces provide for ease of ratcheting.

United States Patent Horton 1 SELF-ADJUSTING OPEN 0R CLOSED-END RATCHET WRENCH [76] Inventor: Billy M. Horton, 3238 Rodman SL,

N.W., Washington, DC. 20008 [22] Filed: May 2, 1973 {21] Appl. No.: 356,429

Related U.S. Application Data [63] Continuationin-part of Ser. No. 203,310, Nov. 30,

1971, abandoned.

[52] U.S. Cl 81/179; 81/139 [51] Int. Cl B25b 13/12 [58] Field of Search 81/77, 126, 127, 129, 130 R,

{56] References Cited UNITED STATES PATENTS 1,721,860 7/1929 Krogel 81/127 X 2,797,600 7/1957 Beaver 81/179 3,641,847 2/1972 Horton r 81/179 X Primary ExaminerAl Lawrence Smith Assistant Examiner-James G, Smith Attorney, Agent, or FirmRose & Edell 1 July 1, 1975 5 7 ABSTRACT A self-adjusting open or closed-end ratcheting wrench that accommodates a range of nut sizes comprises a wrench body with one fixed jaw, a single ratcheting pawl that moves in an arcuate manner so as to fit a range of nut sizes, an elastic actuator mechanism for biasing the pawl to its operating position, and a slide handle coupled to the actuator mechanism to permit installing around a nut. The motion of the pawl places it in the proper position and gives it the proper angular orientation to provide two drive positions for each face of a polygonal nut. In one drive position the nut is driven by three contacting surfaces, and in the other drive position the nut is driven by two contacting surfaces. These two drive positions provide ratcheting every 30" or 60 on a hexagonal nut. Multiple contact surfaces between the pawl and the jaw with which it mates provide high friction during the drive phase of operation but the inclination and curvature of the surtiu um u faces provide for ease of ratcheting.

26 Claims, 34 Drawing Figures a r I y 4 e9 e a \I :1: 1 :7 .tliii i 91 '13 11 11 'mrmimm 1 SHEET Dmd ATTORNEYS PKTFHTFWJULI I975 3,692 150 m vemora B\LLY M. HDRTDH Qo wwl ATTORN EYS "ESIFi FTERJML 1 1975 13 8 9 2 1 5 U SHEET 3 NVENTDK 54 BILLY M. HORTON 7 ATTORNEYS MBQZJSO "RTFTH EMM 1 ms SHEET (mowers MTQITFDJUL] SHEET ATTO RHEYS 1 SELF-ADJUSTING OPEN OR CLOSED-END RATCI-IET WRENCH CROSS REFERENCE The present application is a continuation-in-part of my co-pending application Ser. No. 203,3 l filed Nov. 30, I971, for "Self Adjusting Open-End Ratcheting Wrench", now abandoned.

BACKGROUND OF THE INVENTION This invention relates to new and improved wrenches, more particularly to open and closed-end ratchet wrenches of simple construction that are capable of adjusting themselves automatically to a range of nut sizes while retaining the ability to ratchet.

Open or closed-end wrenches of a particular size are often required to drive a nut or bolt head (hereinafter collectively referred to as nuts") that is appreciably smaller than the size for which the wrench was designed. One reason for this is that manufacturing tolerances permit nuts to be as much as 3 percent below their nominal size. Also, nuts that have been used many times become worn down in size and acquire rounded corners resulting to slippage of the wrench. In addition, nuts made in accordance with one set of standards, e.g., metric, are often nearly the same size as nuts of another system, e.g., American, and it is somewhat of a temptation to a mechanic to employ a wrench of approximately the correct size but which damages the nut because of slippage or because of being forced on the nut. A proper set of self-adjusting wrenches could fit both American and Metric nuts and bolts. Furthermore, it would be a convenience to diminish the number of different wrenches required to fit a particular range of nut sizes, and this reduction in number of wrenches should be reflected in savings of time to perform tasks requiring wrenches.

Open and closed-end ratchet wrenches have heretofore been characterized by limited ability to accommodate nuts of varying sizes. In some the path of motion of the movable jaw does not take into account variations in nut size. Such accommodation as is provided requires awkward movable jaws and in some instances the surfaces contacting the nut can damage the nut surfaces. There is no wrench having a single pawl that provides two drive positions of the wrench for each face of a polygonal nut, as well as self adjustment.

Accordingly, an important object of the present invention is to provide a wrench construction which will obviate the foregoing disadvantages characterizing known wrench structures. Another primary object of this invention is to provide a self-adjusting open or closed-end ratchet wrench.

A further object of this invention is to provide a selfadjusting open or closed-end ratchet wrench having sufficient strength for general utility. constructed by conventional methods at low cost.

Still another object of this invention is to provide an improved self-adjusting open or closed-end ratchet wrench that will automatically adjust itself to the exact size of undersize or oversize nuts and to worn nut and bolt heads.

Another object of this invention is to provide a novel self-adjusting open or closed-end ratchet wrench with a single pawl that is capable of driving a nut in two distinct positions relative to each side of a polygonal nut.

Yet another object of the present invention is to provide a self-adjusting open or closed-end ratchet wrench having a single ratcheting element yet which maintains substantial contact with a nut during ratcheting operations and is consequently self-retaining.

It is another object of the present invention to pro vide a self-adjusting open-end ratchet wrench that can be positioned on a nut from the side using a slide handle to open the jaws of the wrench.

Another object of the present invention is to provide a self-adjusting open or closed-end ratchet wrench that can tolerate widely varying environmental conditions ranging from sand, dirt, and rust, to oil and grease through the use of multiple contact surfaces between the nut and the pawl and wrench jaw.

SUMMARY OF THE INVENTION In the present invention a self-adjusting open or closed-end ratchet wrench employs a single ratcheting pawl and consumes no more space than a conventional open or closed-end wrench of the nonratcheting type. In a preferred embodiment of the invention, the pawl follows an arcuate path in adjusting to nuts of varying sizes and in opening wide to allow the wrench to be inserted over a nut. The center of the circle of which the arcuate path is a sector, is determined by the necessity of having the pawl close down on the nut in the correct position and with the correct angular orientation to securely hold the nut. This center must meet the conditions for easy ratcheting and must also provide sufficient friction to hold the pawl securely in place during the drive phase. An important feature of the present invention is that means are provided for achieving the required frictional forces through the use of multiple contact surfaces rather than by the use of especially roughened or otherwise conditioned surfaces. The multiple contact surfaces make possible a very high effective coefficient of friction using ordinary surfaces.

The angle between the direction of travel of the pawl and a line along the length of the handle is sufficiently large that in one version, the spring force required to bring the pawl into operating position can be better delivered through a sector gear rather than be delivered directly. A compression spring acting through an actuator rod rotates the sector gear which in turn actuates the pawl by means of a second sector gear that is an integral part of the pawl. The positioning of the wrench around a nut is accomplished using the slide handle which compresses the spring and actuates the pawl through the same actuator rod and sector gears as are used for the ratcheting action. In another version of the wrench the jaw end of the wrench is rotated about 20 relative to the axis of the handle so that by using a curved channel for the actuator rod the movable jaw may be driven directly by the actuator rod rather than through a sector gear arrangement.

In the open-end wrench, the end of the wrench has the appearance of a conventional open-end wrench except for the movable pawl. The pawl has a tongue or slide positioned in a slot formed in the wrench at an angle of about 30 with the center line of the wrench handle. In the closed-end version the position of the handle is rotated about l20 relative to the handle of the open-end wrench so that the pawl slide reciprocates generally along the axis of the handle. Other than the location of the handle and the fact that the wrench is a closed-end wrench, the two wrenches are identical.

In the preferred embodiment of the present invention the pawl has two drive positions. In the first drive position the outer end of the pawl provides one contacting surface. The outer end of the fixed jaw provides a second contacting surface, and the throat of the nut opening provides the third contacting surface. The combina tion of three drive surfaces greatly reduces the spreading moment on the wrench jaws because there are more drive surfaces and because the direction of the force delivered by the nut to the wrench fixed jaw is more favorable than in the case of a conventional two jaw open-end wrench. In the second drive position the mid section of the pawl provides a drive surface for the nut and on the opposite side of the nut the fixed jaw provides a single drive surface. The force delivered to the pawl and the fixed jaw by the nut is the same as that required for an equivalent torque by a conventional open-end wrench. however, the angle of the force of the nut on the pawl and on the fixed jaw is more favorable than in the case of a conventional open-end wrench. For a hexagonal nut or bolt head the force is inclined 30 from the direct spreading direction. Furthermore the point of application of the force of the nut against the pawl and against the fixed jaw is displaced inward of the outer extreme of the jaw surfaces. whereas in the case of a conventional open-end wrench one of the jaws experiences a spreading force nearer the outer end of one of the jaws. The above considerations lead to a 30 to 40 percent diminuition of the spreading moment on the jaws of the wrench of the present invention compared with a conventional fixed jaw open-end wrench.

The contour of the pawl and opposite jaw are such that the wrench retains its position on the nut during ratcheting without any effort on the part of the operator. The wrench can, however, still be pulled off a nut or bolt head by simply pulling on the handle.

In a modification of both the open and closed-end wrenches ratcheting occurs only at every 60 instead of every 30 as in the prior embodiments. For reasons to be described subsequently, such an arrangement permits the use ofa straight rather than a curved pawl slide and wrench and pawl engaging surface thereby reducing the cost of fabrication. Further the wrenches which ratchet only at 60 angles may accommodate a range of nut sizes which vary 20 percent whereas with the prior embodiments the wrenches can accommodate a range of nut sizes of only l percent. Thus only half the number of wrenches are required to accommodate a given range of sizes, for instance. A inches to 1 1/16 inches, as with the wrenches of the prior embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS The above and still further objects. features. and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings. wherein:

FIG. I is a plan view of one-half ofthe wrench of the present invention;

FIG. 2 is a plan view of one-half of the wrench of the present invention with the cover plate removed;

FIG. 3 is an edge view of the wrench taken along section 3-3 of FIG. 2;

FIG. 4 is an illustration of the positioning of nuts of two different sizes in the fixed jaw of the wrench.

FIG. 5 is the same as FIG. 4 but the nuts are rotated 30 in the jaw;

FIG. 6 is an illustration ofthe method of determining the effective center of rotation of the pawl that will properly follow a nut which recedes into the fixed jaw shown in FIG. 5;

FIG. 7 is an illustration of the wrench with the pawl reapplied and the relationship of R and III thereto;

FIG. 8 is an illustration of the friction forces that hold a pawl in place during the drive phase for a nut in the first position;

FIG. 9 is a vector diagram of the forces acting on the apparatus of FIG. 8;

FIG. I0 is an illustration of the same forces as shown in FIG. 8 but rotated to the second drive position;

FIG. 11 is an illustration of the restrictions on the selection of the center of rotation of the pawl that will allow proper ratcheting to take place;

FIG. 12 is a composite of FIGS. I, 2, 8, l0 and II showing the restrictions on the center of rotation of the pawl based on both the drive and the ratcheting considerations;

FIG. I3 shows a second way of achieving a high effective coefficient of friction by means of the V groove principle;

FIG. 14 shows a way of achieving a very high effective coefficient of friction by combined use of the V groove and multiple layering;

FIG. I5 is a side view in elevation of the arrangement of FIG. 14;

FIG. 16 is a front view in elevation of a yoke employed to support one of the layers of FIG. 14;

FIG. 17 is a plan view with the cover removed of an embodiment of the invention utilizing a single compression spring for control of the pawl;

FIG. 18 is a top view of an embodiment of the wrench from which the sector gears have been eliminated;

FIG. 19 is a figure taken along section 19-19 of FIG. 18;

FIG. 20 is a figure taken along section 20-20 of FIG. 18;

FIG. 2] is a figure taken along section 2l2l of FIG. 18'.

FIGS. 22 and 23 are schematic diagrams illustrating in detail the contours of the interionof the stationary jaw and also illustrating the method of deriving these surfaces;

FIG. 24 is a side view in elevation of a modified form of the wrench of FIG. 18;

FIG. 25 is a top view of the wrench of FIG. 24;

FIGv 26 is a view of the jaw structure of the wrench of FIG. 24 with the pawl removed;

FIG. 27 is a detailed view of the pawl of the wrench of FIG. 24;

FIG. 28 is a sectional view taken along 28-28 of FIG. 26;

FIG. 29 is a sectional view taken along 29-29 of FIG. 24'.

FIG. 30 is a partial side view in elevation of a closedend wrench according to the present invention;

FIG. 31 is a sectional view taken along 313l of FIG. 30;

FIG. 32 is a partial view in elevation ofa modification of the wrench of FIG. 18;

FIG. 33 is a partial view in elevation of a closed-end version of the wrench of FIG. 32; and

FIG. 34 is a partial view in elevation of a modification of the wrench of FIG. 33.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now specifically to FIGS. 1, 2 and 3 of the accompanying drawings. there is illustrated a plan view of one end of the wrench of the present invention; FIG. 2 illustrating the same view as in FIG. I except that the cover plate has been removed. The wrench comprises a fixed jaw generally designated by the reference numeral I and a movable jaw or pawl designated by the reference numeral 2. The jaw 1 comprises exteriorly a continuous arcuate surface S and interiorly a number of flat intersecting surfaces commencing at the tip of a finger-like end member 3 in a first flat surface 4. Additional surfaces generally designated by the reference numerals 6, 7, 8, 9, 10, II, 12 and 13 progress in a clockwise motion about a generally arcuate path terminating in a curved surface 14 commencing just slightly clockwise of the center line of axially elongated handle I6 of the wrench. The pawl or movable jaw 2 is moved along a path generally concentric to an arcuate surface 20 extending from surface 14 to the exterior of the wrench; movement of jaw 2 being controlled by a mechanism to be described subsequently. The pawl 2 provides a nut engaging surface 18 having a shallow but wide. V-shaped depression 15 defining second nut engaging surface 17 along the right surface of the V" as viewed in FIG. 1.

In the particular embodiment illustrated in FIG. 2, the pawl 2 slides on two elongated upward projections or tongues 19 which rise from the main body of the wrench to the left of the surface 20; the two members 19 being isolated from one another by a deep recess 21 for receiving a slide 22 which is an extension of the pawl 2. The pawl is recessed at locations 23 on opposite sides of the slide 22 to receive the upward projections I9 of the main body of the wrench; the projections 19 being of such a length as illustrated in FIG. I as to always have a portion of the pawl 2 seated thereon even when the pawl 2 is in its innermost or outermost position both as illustrated in FIG. 1. The projections 19 being seated in the recesses 23 provide a guide for the movement of the pawl 2 and further greatly increase the friction between the pawl and wrench for purposes to be described subsequently.

The slide 22 is received in a recessed section 24 of the main body of the wrench toward the handle 16; the slide extending inwardly of an unrecessed region 26 of the wrench which defines the surfaces 12, 13 and 14 at its left (in this arrangement) surface and provides an arcuate surface over which the left surface of the slide 22 is guided. The right surface or handle side of the slide is provided with a series of gear teeth to constitute a sector gear 27 which is engaged by a sector gear 28. also located in the recess 24 in the main body of the wrench and pivoted for movement about a pin 29. Clockwise and counterclockwise rotation of the sector gear 28 produces inward and outward movement, respectively, of the pawl or movable jaw 2 in FIGS. 1 and 2 so as to decrease or increase the distance between the movable jaw and opposed portion of the fixed jaw of the wrench.

It is apparent from the description that the pawl is not only guided on the tongues 19 but also by interaction of the slide 22 and the right wall 25 of the unrecessed section 26 of the main body of the wrench; the slide 22 being maintained by the sector gear 28 in contact with the surface 25, regardless of its position, within the bounds of its movement.

The sector gear 28 is biased in a clockwise direction about the pivot pin 29 by means of a rod 31 seated in an axial slot 32 cut in the handle of the wrench. The rod 31 is connected to the remote end of a compression spring 33 seated in a widened recess 34 approximately in the center of the handle 16 of the wrench.

When it is desired to expand the jaws of the wrench. a slide handle 36 which is slidably retained at the center of the handle, is pushed towards the jaw under discussion and carries with it a pin or stud 37 positioned, as illustrated in FIG. 2, at the end of the compression spring remote from the jaw. Movement of the slide causes the pin 37 to compress the spring 33, push the rod 31 towards the jaws, rotate the sector gear 28 counter-clockwise about the pivot pin 29 and cause the slide 22 to move in a direction to increase the distance be tween the movable and fixed jaws of the wrench. thereby permitting the jaws to be applied to a nut.

The mechanism illustrated in FIG. 2 is normally covered by a cover plate 35 which conforms exactly to the configuration of the entire wrench; the cover plate being suitably secured by screws or other suitable removable mechanism so that the operating mechanism is maintained in place but the cover may be removed for repair if necessary.

The wrench is conventionally a double-ended wrench, in which case the mechanism illustrated in FIGS. I and 2 finds a mirror image except for size at the other end of the wrench. It is possible however to employ a single compression spring. This embodiment is illustrated in FIG. 17 and is discussed subsequently.

Referring now specifically to FIG. 4 of the accompanying drawings, there is illustrated the wrench of FIGS. I and 2 having a hexagonal nut 38 positioned within its jaws in a first of two possible positions. In the position illustrated in FIG. 4, the wrench engages the nut at the surfaces 4, I3, and I8 and thus provides three specific driving surfaces between the wrench and the nut which is one more driving surface that is provided by an ordinary open-end wrench. Also, since one of these driving surfaces is at the throat of the wrench. no spreading moment is developed at this point. The wrench may be ratcheted 60 relative to the nut in which case the nut again assumes the position relative to the wrench illustrated in FIG. 4. However, if limited room for ratcheting is available, then the wrench need be ratcheted only 30 in which case the nut 38 takes the position illustrated in FIG. 5 of the accompanying drawings. In this position the nut is driven by the driving surfaces 7 and 17 of the wrench. The wrench now provides two surfaces of contact which is the same as in the conventional open-end wrench. It should be noted however that the angle of the force of the nut on the pawl and the fixed jaw is inclined 30 from the line of the force that would give maximum spreading due to the angles of the surfaces of contact. Also. the force is not applied at the end of either the jaw or the pawl and the lever action tending to spread the jaws is lessened. Thus under the least desirable conditions of operation, i.e.. only two driving surfaces. the wrench of the present invention undergoes a considerably lessened spreading moment of its jaws compared to a conventional openend wrench of comparable dimensions; and in its other position when there are three driving surfaces it has a very much reduced tendency to spread and thus has a greater gripping force on the nut than the conventional open-wrench of comparable dimensions. In this context it should be again noted that one of the surfaces of contact 13 is at the base of the jaw in a region of maximum strength.

As previously indicated. the wrench of the present invention has another distinct advantage over the conventional open-end wrenches in that it accommodates different size nuts with one jaw and in fact will span the American standard and Metric system nuts in a given range. This can be readily seen by again referring to FIG. 4 of the accompanying drawing. It will be noted that there is provided a dash-line outline generally designated by the reference numeral 38'. This nut engages the same surfaces of the wrench as the larger nut 38 but in this instant the pawl 2 has moved inwardly along its arcuate path to accommodate the smaller size of the nut. It is quite important to note that as indicated immediately above. the smaller nut 38' contacts the identical surfaces as the larger nut 38. In FIG. 5 the pawl or movable jaw 2 engages the nut adjacent an apex generally designated by the reference numeral A relative to the nut 38" and the apex A of the reference numeral 38". Relating the location of the apexes A and A relative to the handle of the wrench, it can be seen that the point A has moved both towards the stationary jaw of the wrench and towards the handle of the two extremes as indicated by the points A and A. Also it can be seen by referring to FIG. 4 that the surfaces of nuts 38 and 38' are inclined relative to one another so that the pawl 2 must follow a generally arcuate path in order to seat flush against the surfaces of the two different size nuts.

In order to find the center of this arcuate path, a line 41 is drawn between the two points A and A. FIG. 6 illustrates portions of the nuts 38" and 38" in the same relative positions as illustrated in FIG. 5 but on a more expanded scale. The center of the path through these two points must lie along the perpendicular bisector 42 of the line 41, the line 42 then being the locus of all the possible centers of arcs that pass through A and A.

It has been found that specific advantages are achieved if the distance from the intersection of the lines 41 and 42 to the center about which the pawl 2 rotates is in the range of approximately 3 to 4 times the distance from the center of the nut to the center of a flat surface of that nut of maximum size for which the particular jaw is designed; this distance being l /2 to 2 times the flat-to-flat width of a hexagonal nut. In this range approximate alignment of the pawl faces 17 and 18 and the adjacent surfaces of the nuts lying in the design range is obtained. Slight deviations from this range are permissible if lesser alignment can be tolerated in specific applications.

Referring now to FIGS. 6 and 7, an arc 40' of the engaging surfaces of pawl 2 and the tongues 19 is drawn from a center having a length from the center of the line 4] equal to approximately 1% (or in a range of 1V2 to 2) times the maximum width of nut for which the wrench is designed. The radius is obviously somewhat larger when extended to the interlocking or sliding sur' faces of the tongues I9 and the recesses 23 in the back surface of the pawl 2. The engaging surfaces of the slide 22 and the unrecessed portion of the member 26 should be struck from the same center.

The radius R is actually found by the following formula:

.S S RT-X 57.3 U or rearranging: R 57.3 E-

where 6 is the angle in degrees between lines I and v (the lines of the faces of surface 13 at its extreme positions) of FIG. 6 and S is the length of the are corresponding to the line 41. The length of the line 4] is determined by the range of sizes of nuts to be accommodated by the wrench. The range should not exceed 7 to 10 percent of the maximum nut suze so that contact between the nut and the surface size occurs over onethird or more of the surface 13. As to the angle 0, as the nut sizes decrease, the angle of the face of the nut contacted by surface 18 of the pawl rotates slightly counter-clockwise as viewed in FIG. 6 (lines I and y) and the pawl surface 18 must rotate to accommodate the nut rotation. The above formula is based on the fact that the arc length divided by the radius is equal to the angle of rotation of the pawl in radians. The chord can be used in place of arc length so long as the angle is relatively small.

By employing the above construction, the surface 18 of the pawl 2 moves inwardly to accommodate units of smaller and smaller size in such a manner that the surface 18 is rotated to accommodate the rotation of the adjacent surface of the nut thereby insuring an extended contact between the nut and pawl surfaces.

The location of the center of the circle along the line 42 imposes certain requirements upon the frictional forces necessary to be developed between the nut and the pawl and the pawl and the main body of the wrench to achieve satisfactory operation. Reference is now made to FIG. 8 of the accompanying drawings. It must be understood initially that the compression spring 33 cannot conceivably provide the force necessary to hold the pawl 2 in place, against the forces involved in tightening a nut. If the spring were strong enough to provide such a force, the average person could not operate the slide 36 to open the jaws and if they could it would be with such great difficulty as to render the wrench impractical. Thus, it is necessary for the friction forces developed between the nut and the pawl and the pawl and the wrench to achieve the necessary holding forces. In FIG. 8 the vector F is the normal force of the wrench jaw upon the pawl, and is drawn for the situation where the surfaces between the pawl and the jaw are flat surfaces having a normal coefficient of friction for machine tool steel. The vector F,- is the maximum frictional force that can be developed by the coefficient of friction pt, and the vector force F,- F,. is the force exerted on the pawl by the nut and the vector ;.t,,F,, is the maximum frictional force that can be developed by the friction between the surfaces therein involved. The coefficient of friction is chosen for machine tool steel with no special preparation of surfaces to increase friction coefficient, normally about 0.I 0. IS.

The vector diagram of FIG. 9 is derived from the physical arrangement illustrated in FIG. 8 for the situation when the nut and wrench have the relationship illustrated in FIG. 4, that is for the three point drive. If F,- and F,, are the respective normal forces of the jaw and nut on the pawland slippage has not occurred. then a closed forced diagram or set of vectors is defined since the system must be in balance.

The diagram of FIG. 9 illustrates the fact that if the vector F; cannot be increased. which it cannot be for engaging tool steel surfaces, then the angle II! is at a maximum and the direction of application of F; cannot be increased; that is. the vector F cannot take a direction that brings it into the lined region to the right of the projection of vector F j as viewed in FIG. 8, in which region, as seen in FIGS. 7 and 12, the center 40 lies. Thus the requirements for location of the center 40, which determines the ability of the wrench to accommodate nuts of different sizes. cannot be met by a construction employing flat mating surfaces of machine tool steel.

Reference is now made to FIG. 10 of the accompanying drawings which illustrates the force action upon the pawl for the nut position of FIG. of the accompanying drawing. The situation in FIG. is the same as in FIG. 8 but rotated 30. Again it is quite apparent that sufficient friction between the pawl and mating parts of the wrench is not provided to insure that the center 40 lies in the region in which slippage between the pawl and adjacent wrench parts can be prevented.

Another factor that must be considered in designing the wrench of the present invention is the relationship necessary to insure that the pawl 2 does not bind during ratcheting and the considerations involved therein are illustrated in FIG. 11 of the accompanying drawings. During ratcheting, the nut, regardless of which of the positions it is in; that is, the position illustrated in FIG. 4 or FIG. 5, may pivot about point 43 of the fixed jaw I; the lower jaw illustrated in FIG. II. The point 43 is the point of intersection of the surface 4 and the surface 5 forming the outer contour of the jaw I. If the contacting surfaces of the pawl 2 and the fixed adjacent jaw have a center of curvature lying in the shaded area of FIG. I], then upon the nut pivoting about point 43 an outer or upward force is exerted on the pawl, as viewed in FIG. II, and the pawl is jammed against the mating surface of the fixed jaw and tends to bind thereby impairing the ratcheting action. A lubricant could be employed to reduce the friction but this would also reduce the friction during tightening of the nut and is therefore obviously undesirable. However, if the center of the mating surfaces of the pawl 2 and the adjacent or upper jaw as viewed in FIG. 11 lies in the region to the right of the shaded portion of FIG. 1 I, the force exerted by the nut during ratcheting either causes the pawl to follow exactly the contour of the mating surfaces, this occurring when the arc is struck from the point 43, or tends to unseat the pawl slightly from the mating surfaces when the center lies to the right of the shaded area of FIG. 11. Thus, even if the friction between the pawl and the adjacent or upper jaw of FIG. 11 is high, the ratcheting action is unimpeded since the pawl is unseated during the ratcheting action.

Referring now specifically to FIG. I2, the diagrams of FIGS. 8, I0 and 11 are superimposed upon one another with the cross-hatched regions indicating the prohibited regions. The center of curvature. if it is to conform to all the restraints imposed by the discussion relative to FIGS. 8-11, may lie only in the open (unshaded) region and if it does. high friction forces are exerted when tightening a nut and unimpeded ratcheting is accomplished. It will be noted however that the center of the curvature of the mating surface between the pawl and the adjacent jaw, which is designated by the reference numeral 40 and which is derived from the diagram of FIG. 7, lies in one of the shaded regions to the right of the permissable region for obtaining the necessary friction during tightening of a nut. Thus the two requirements are not compatible. It will be remembered however that the vectors of FIGS. 8 and I0 are based upon normal friction forces which can be expected between relatively smooth surfaces of the types of metal which would normally be employed in manufacturing wrenches of this type. It is apparent from FIG. 12 that something must be done to increase the angle ll! of FIG. 9 in order that the center 40 not lie in a shaded region.

Reference is again made to FIG. 3 of the accompanying drawings which illustrates one of the methods which is employed to accomplish the aforesaid purpose. The strong binding force which is achieved between the pawl and the adjacent jaw as a result of the use of the elongated tongues 19 and the recesses 23 in the pawl, has been found sufficient to permit the use of an angle ll] that rotates the unshaded region of FIG. I2 counter-clockwise (rotates vector F,-) to encompass the center 40 illustrated therein. When proper coefficients of friction are developed in the various ways discussed subsequently, all requirements for a satisfactory openend ratchet wrench which can accommodate nuts of sizes which vary 8% to 9% are met. Specifically a center of curvature for the pawl and wrench body can be utilized which insures proper tracking of the pawl relative to adjacent surfaces of different size nuts insuring that friction forces are developed which provide the pawl holding forces required to permit adequate tightening of a nut to be driven by the wrench.

Other arrangements may be employed to increase friction, examples of such being illustrated in FIGS. 13 and 14. In FIG. 13, the wedging tongue and groove arrangement is again employed but a single tongue 46 is utilized on the stationary portion of the jaw and the single groove 47 is provided to receive the tongue 46 of pawl 2. The wedging action is again developed with about the same friction forces as in FIG. 3. The arrangement of FIG. 3 has the advantage that the tongues 19 are in alignment with the regions of the handle of major strength, the center of the handle being grooved at 31 and therefore being of lesser strength than the remainder of the handle. Also, the contact between the pawl and main body provided in FIG. 3 is forward of the contact provided in FIG. 13 and is more nearly over the nut.

The friction force that is developed between the tongue 46 and the side walls of the groove 47 of FIG. 13 and the corresponding parts of FIG. 3 is a function of the angle 5, the angle between a line 45 perpendicular to the vertical axis of the parts illustrated in FIG. I3 and a line 50 drawn perpendicular to the surface of the groove 47 contacting the tongue 46. The eclor forces F F and F are related by the equation F +F =F and in terms of vertical components, assuming the two sides are equal, F sin8 F sinS 2F sins F The friction forces are related by the equation The effective coefficient of friction, u, is given by Thus the effective coefficient of friction of the arrangement of FIGS. 3 and I3 is equal to the coefficient of friction of the contacting surfaces times the cosecant of the aforesaid angle 8 which is the angle between the surface of the groove 47 and the side of the wrench as viewed in FIGS. 3 and 13.

Applying the above to the wrench in question, if p. 0. l 5, a normal oily metal-to-metal surface, then a p. of 0.7535 will provide a sufficient effective coefficient of friction to realize the objects of the invention as dia grammed in FIG. 12. This requires that 8 Il /2 or less. The selection of 5 for any particular wrench is thus a function of the coefficient of friction of the surfaces in contact and the p... required to provide the force necessary to prevent slippage of the pawl 2.

Precise determination of the angle 5 may be accomplished by first determining the angle i): required to prevent pawl slippage and to insure proper location of the center 40. The coefficient 1.1. available with the material employed to fabricate the wrench must then be deter mined. With these values known the angle 6 may be calculated from the formula lb tan lu csc 8].

For normal conditions the 6 will lie in the range of l to l and will produce a good drive force without binding during ratcheting.

In FIGS. 14 through 16, a multilayering arrangement is utilized wherein friction materials are arranged and retained in the space between the tongues and grooves 46 and 47 as illustrated in FIG. 13. The layers of fric tion materials, designated by numerals 48 and 49 respectively, are carried by the parts 46 and 47 respectively and provide a high degree of friction. The multilayering arrangement may also be employed without the tongue and groove arrangement 4647 and specifically with flat surfaces of contact. These arrangements can be used where high coefficients of friction are required.

Referring specifically to FIGS. 14-16, a yoke 48' is pivotally secured to the body of the wrench and carries in the region between pawl and wrench body the member 48 which is preferrably of the same or higher coefficient of friction material as the wrench body. The member 49 is made of the same material and is carried on the slide 22 which passes through an opening 55 therein. The opening 55 is slightly larger than slide 22 and moves parallel to the adjacent surface of the wrench as the pawl moves. The yoke 48' is slotted at 60 so that the slide 22 may move without interference.

It will be noted that the member 48 which is attached to the main body of the wrench is disposed between the member 49 and the pawl. Thus, when the wrench is driving a nut, each of members 48 and 49 is clamped between two surfaces of the other member and very high effective coefficient of friction may be obtained.

It can be seen from the above that the wrench of the present invention provides a ratcheting end wrench which insures tight gripping of the nut during tightening but permits ease of ratcheting. The nut is seated in the wrench so that the tendency to spread the jaws is less than in a standard end wrench in all positions even though the wrench can accommodate nuts of size differences of up to 8 to 9 percent. The wrench may he slipped onto the out from the side by use ofthe slide or center control and may be withdrawn from the nut by merely pulling on the handle which causes the pawl to spread and permit easy withdrawal of the wrench.

The wrench has been described as applied to a hexagonal nut but it is readily apparent that with slight modifications of the internal contours of the jaw and pawl the wrench may be made in a form to accommodate nuts of other shapes, for instance, pentagonal. The principles set forth above apply with equal validity to such additional configurations even though angles and arcs of various parts are changed.

FIG. 17 is a partial view of an arrangement employing a single compression spring 51 as previously discussed. In this instance a rod 52 passes through a spring and is anchored to its right end and a rod 53 passes through the spring and is connected to the left end of the spring. Two actuating pins 54 and 56 are provided to the left and to the right respectively of the spring SI so that when, for instance. the slide, which is designated in the Figure by reference numeral 57, is moved to the right, the rod 53 rotates its associated sector gear 28 in FIG. 2, opening the jaws of the wrench. If the slide 57 is moved to the left, pin 58 engages the spring, moves the rod 52 to the left and opens the jaw associated with the sector gear driven by the rod 52.

In the above embodiments of the invention, the movement of jaw 2 is accomplished by means of the sector gear arrangement to accommodate the almost transverse movement of the jaw 2 relative to the con trol cable or wire 53. In some situations this arrangement may be undesirable, particularly where manufacturing a wrench to a low cost. The sector gear arrangement may be eliminated in accordance with the embodiment of the invention illustrated in FIGS. 18-21. In this arrangement, the jaw and pawl structure comprising the members I and 2 is rotated approximately 20 clockwise, as illustrated in FIG. I8, relative to the axis of the handle I6. The channel 32 of FIG. 2 has its counterpart in FIG. 18 designated by the reference nu meral 32' and in this instance is curved from the spring retaining region 34 to a shoulder or projection 57 formed on the handle side of the member 22 of the pawl 2. In this instance, the member 22 is smooth on the handle side except for the projection 57 and specifically the rack gear teeth are removed. The curved channel 32 extends at an angle from region 34 and sweeps on a continuous curve from a position a short distance from the right of the region 34 in a counterclockwise direction to provide a relatively continuous, smooth curve for a guidewire 31' extending between spring 33 and the shoulder 57.

In this embodiment of the invention, when the end of the spring 33 is compressed toward the right, as illustrated in FIG. 18 by means to be described subse quently, the rod or wire 3I' causes the jaw 2 to be moved along its arcuate path, opening the jaw so that the wrench may be placed on a nut. The operation of the device is the same in FIG. 17 in the other figures of the invention except of course for the elimination of the rack and pinion arrangement.

In this embodiment of the invention. all of the grooves and recesses are formed in a base member designated in FIG. 19 by the numeral I6. The channels are covered by an upper base member 16" which is riveted to the member 16 or secured thereto by means which permit the upper member to be removed if required for repair.

The arrangement of the spring, wire and slide members in the region of the spring 33 is illustrated in FIG. 18. In this arrangement the structure is much the same as in FIG. 2 except that a slot designated by the reference numeral 58 is formed in the section 16' to provide a guide for a shoulder 36' formed on the slide 36 associated with that side of the wrench. The slides 36 are secured together by two rivets or removable studs designated by reference numeral 59 which serve to move a slide 6| positioned in the space 34 between the two springs 33. When the slides 36 are moved to the right, for instance. as illustrated in FIG. 16, the slide 6] engages the left end of the spring 33 compressing it to cause the jaws to open. The slide 61 constitutes an inner extension of the righthand slide 36 illustrated in FIGS. 18 and 19 which is seated in the region 34 and as indicated previously is held to the other or left side member 36 by the two studs or securing means 59. Again, as illustrated in FIGS. I8 and 19, the left side of the region 34 provides a guide or slide surface for the upper and lower portions of the slide 61 as illustrated in FIG. 21.

It can be seen from the embodiment of the invention illustrated in the FIGS. 18-21 that the operation of the device is entirely feasible without the use of rack and sector gears if the jaw of the wrench is rotated relative to the handle. As also indicated above, the rotation of the head and or jaw need be approximately only 20 relative to the axis of the handle to accomplish the desired result.

The inner contours of the stationary jaw I are quite important to proper operation of the wrench and for a full explanation of these contours and how they are derived, reference is made to FIGS. 22 and 23.

The heavy solid line of FIGS. 22 and 23 illustrates surfaces corresponding to a conventional 12 point socket as related to the jaw 1 of the wrench of the present invention. The heavy dashed line of FIG. 22 illustrates the contour of jaw I as modified to accommodate a l percent variation in nut sizes in the 60 position, the portion of the jaw removed to affect such accommodation being shaded in the drawing.

The accommodation of a percent variation in nut sizes is chosen for the following reason. If only an 8 percent variation is accommodated, then the wrench will accept nut and bolt heads having variations within specifications and can handle most common American and metric sizes within the range. If a 9 percent variation can be accommodated, then nut and bolt heads slightly out of specification and worn heads can be accommodated as well as American and metric sizes within the range. In order to accommodate heads in the 9 percent range, the wrench must be designed to accept a variation of 10 percent so that relatively unimpeded ratcheting can occur.

Referring specifically to FIG. 22, the solid light line illustrates a maximum size nut in the 60 position and the dashed light line is the 10 percent smaller nut also in the 60 position.

The interior surfaces of major consideration of the jaw 1 for both positions are 4, 6, 7, l2 and 13 and in a conventional 12 point socket they form angles of +60", 0", l50, 90 and +l respectively (with counter-clockwise being positive) with a diagonal of the nut which is parallel to the surface 6. The surfaces 4, 7 and 13 are drive surfaces and conventionally have a length of 0. l 547 times the flat-toflat width of the nut.

When a full size nut is driven in the position. the full length of the surfaces 4 and 13 contact the nut and drive it. In this case, no modification of the conventional I2 point configuration is required. In the case of a l0 percent reduction in size however the surface 9 must be relieved. In order to insure that the nut remains properly positioned relative to the pawl 2 and the surface 4, the surface 6 is employed to provide a fixed surface against which the nut is biased by the force of the pawl thereon. With an undersized nut, the center of the nut moves from point G of FIG. 22 toward the surface 6 and with a 10 percent reduction in size the nut center moves to point B, the point G being the location of the center of a maximum size nut in both 30 and 60 positions.

Since the nut is contacted by the surface 4 during driving and is held against the surface 6 by action of the pawl, the IO percent reduced size nut assumes the position illustrated in FIG. 22. It is readily apparent that the surface 9 must be relieved and specifically to the extent indicated by the shaded region in order to permit the It) percent reduced size nut to contact surfaces 4, 6 and I3.

Referring now to FIG. 23, the shaded regions indicated the surfaces which must be relieved to accommodate a 10 percent under maximum size nut in the 30 position. In this position, surface 7 is the driving surface. For the maximum size nut, the various surfaces may again correspond to the 12 point socket wrench. However, with the nut of 10 percent reduced size, the surfaces 8 and 11 must be relieved. In this drive position, the intersection of surfaces 7 and 8 serves the same function as the surface 6 in the 60 position, that is, provides a fixed location against which the nut is pressed by the pawl and thus constrains nuts of decreasing size to follow the curved path 41 of FIG. 6 and also constrains the center of the nuts to move along the path defined by points G and C of FIG. 23.

It will be noted, that in order to accommodate the 10 percent reduced size nut, the surfaces 8 and 11 must be relieved to the extent indicated by the shaded regions. The surface 9 in FIG. 23 is as indicated in FIG. 22 and thus the interior contour of the jaw l in FIG. 23 is a final contour which may be employed.

If desired, the interior surface of the jaw I may follow dashed F between the points D and E. None of these surfaces are utilized in driving but several factors must be considered in determining, in a specific case, whether or not the surfaces 8-1] should be eliminated. These surfaces tend to cause the wrench to maintain good alignment with the nut during ratcheting; they add material to the jaw and therefore strengthen it and also tend to make the jaw look more like a conventional device which may be beneficial for marketing. Removal of these surfaces tends to make ratcheting easier and reduces the cost of the wrench since curve F between D and E is simpler to form than surfaces 8-11.

In order to reduce the cost of manufacturing the designs of FIGS. 1 through 23 the embodiments of FIGS. 24 through 29 may be employed. In the construction of these devices the design is simplified so that the main body of the wrench may be fabricated from a single forging. In this design the pawl is modified so that the unitary slide 22 of the prior embodiment is divided into a yoke which rides in grooves formed in the outer surface of the thicker head part of the wrench. Further the slot for the push rod is formed in an outer surface of the wrench, these two changes eliminating many of the machining operations required in the prior embodiments. The wrench illustrated in FIGS. 24 through 29 basically conforms to the design of the wrench of FIG. 18; however. in addition to the changes noted above, the position of the head is rotated approximately relative to the embodiment of FIG. 1 so that the two sector gears may be eliminated. This latter change eliminates two parts which are subject to wear and simplifies assembly of the wrench. The total effect of these changes is to simplify construction, increase strength and reduce costs.

Referring now specifically to FIG. 24 the wrench is provided with a handle 66 and two enlarged side re gions 67 and 68 at each end of the wrench to provide the conventional heads of the wrench. Arcuate slots 69 and 71 are formed in the enlarged regions 67 and 68 respectively, of the head end of the wrench, to receive arcuate fingers 72 and 73 constituting the members of a yoke of the pawl 74 of the wrench. The head of the wrench is recessed to the width of the handle in a region 76 to fit within the confines of (between) the slides 72. 73 of the pawl 74.

The end surface 77 of the region 76 is splined to pro vide ribs 78 and 79 with a groove 81 disposed therebetween and groove-like regions 82 and 83 disposed exte' riorly of the members 78 and 79. The pawl 74 is provided with a mating splined region 84 providing a central rib 86 which is adapted to be disposed in recessed region 81 and outer ribs 87 and 88. The regions 77 and 84 are adapted to mate to provide the type of frictional engagement previously described relative to FIG. 3 but with the slide 22 replaced with the fingers 72 and 73.

A push rod 89 is disposed in a slot 91 formed in the outer surface of the handle 66 and extends from the far end of a compression spring 92 located in an open central region 93 in the handle to the region of the pawl where the end of the rod 89 is turned at generally a right angle and extends into a hole or aperture 94 formed in the inner side of finger 73 of the pawl 74.

In all respects the wrench of the embodiments of FIGS. 24 through 29 is identical in operation with the wrench of FIG. 18 but certain advantages have accrued from the change in the construction which specifically relate to replacing the center slide 22 of the pawl with tvo outwardly arranged extensions or fingers 72 and First of all the main body of the wrench can be 'xade by a single forging. The slot 91 is formed in the surface of the wrench and to accommodate the formation of this slot the enlarged region 68 of the head end of the wrench is formed as a cover which is riveted or otherwise secured to the main body of the wrench so as to simplify construction. Additionally no regions of reduced width except for the small slot 91 are formed at the head end of the wrench and thus the strength of the handle is carried through into the head of the wrench. Further the construction of the pawl is such that its strength is increased due to distribution of the strain on the pawl over a considerably larger region, specifically over fingers 72, 73.

An additional feature of the invention is that all of the ridges or splined members of the pawl 74 can be 16 formed by a single machining operation by mounting the blank for the pawl on a jig which rotates about the center of the arcuate surfaces as defined in FIG. 7 of the accompanying drawings. All grinding operations can be performed once the pawl is set in the jig and this includes formation of the splined region 85.

The present invention has thus far been described as applicable only in terms of an open end ratcheting wrench. However the principles of the invention are equally applicable to box end wrenches and for a show ing of a wrench of this type, reference is made to FIGS. 30 and 31 of the accompanying drawings. In the em bodiment of the invention illustrated in FIGS. 30 and 31 the nut engaging surfaces of the main jaw of the wrench may be identical with those previously illustrated in FIG. 1 and the reference numerals relating to the various surfaces provided by the jaw are reproduced in FIG. 30. Likewise the nut engaging surfaces ofa pawl 96 of the embodiment of FIG. 30 are identical with those of prior figures and bear identical reference numerals, specifically numerals 17 and 18.

The location of the handle 97 of the embodiment of FIG. 30 is rotated roughly 120 relative to the handle 16 of the embodiment illustrated in FIG. 18. The pawl in this embodiment of the invention is a generally arcuate member which is arcuate about center 40 as defined previously in FIG. 7. The surfaces 17 and 18 are formed at the box end of the pawl and the body of the pawl has formed along its sides splines 98 and 99 which mate with grooves 101 and 102 formed in the handle 97 of the wrench. As in previous drawings the pawl is biased to its extended position by a push rod 103 cooperating with a compression spring located in the handle but which is not illustrated in this Figure.

An arcuate surface 104 is defined by a web of material extending from the point 5 of the main jaw of the wrench to adjacent the recessed region adapted to receive the pawl 96 in the handle of the wrench. The surface 104 is recessed so that it does not contact the nut. In the embodiment of FIG. 18, the material defining surface 104 does not exist since the embodiment of that Figure is an open end wrench. However in the present embodiment, this material is included to form a box end wrench. This web of material also serves another purpose. In the wrench of FIG. 18 rotation of the wrench causes the pawl to press against the short end of the jaw of the wrench, a region somewhat weaker than the handle. Since the handle in the embodiment of FIG. 30 has been rotated the pawl now pushes against the wrench body rather than the jaw. The web of material as defined by the surface 104 and the outer contour of the wrench provides the strength necessary to prevent spreading of the main jaw under all but the most extreme forces. Other than the above changes, that is the rotation of the handle by 120 from the position it occupies in the embodiment of the invention iI- Iustrated in FIG. 18, and the consequent change in the pawl due to the fact that it now slides into the handle. the operation of the wrench is substantially identical with that of prior FIG. 18 except that the invention has now provided a box end wrench. The embodiment of FIGS. 30 and 31 may be fabricated as the embodiment of FIGS. 18 or 24.

It should be noted that it is not necessary to form the spIineJike members 98 and 99 of FIGS. 30 and 31 on both upper and lower surfaces of the pawl as viewed in FIG. 30. The splines may be formed on only a single surface particularly the upper surface as viewed in FIG. 30. However the slot formed in the handle 97 is fabricated by grinding and the grinding wheel must have the surfaces formed thereon which correspond with the spline members 98 and 99 of the pawl. Thus both sides of the channel 100 may be formed in a single grinding operation and nothing is really gained by not providing the grooves on both surfaces of the slot except perhaps the fact that the pawl must then be splined on both surfaces. Either construction is acceptable and the specific final configuration will depend on the choice of the fabricator.

The construction of the wrench provided in the aforesaid embodiments of the invention permit the wrench to accommodate variations in nut sizes from approximately 8 to I percent so that in order to accommodate the normal complete range of nut sizes, i.e. from V4 to l I/l6 inches, both American and Metric units, roughly 16 different heads are required. Using double ended wrenches, which are conventional, 8 distinct wrenches are then required.

A modification of the present invention permits the aforesaid range of nut sizes of both American and Metric to be accommodated with only 8 distinct heads disposed on four wrenches. In order to accomplish this result, the range of sizes which must be accommodated by any single head must be 20 percent and this is achieved at a sacrifice of certain features of the prior embodiments of the invention. Specifically in the embodiments to be discussed hereinafter, the ratcheting can only take place with a 60 rotation of the wrench; i.e. the ratcheting at the 30 intervals must be abandoned. It should be noted that when the wrench is designed to accommodate 20 percent variations in nut sizes and the pawl is in a position to engage the smallest nut size of its range, the jaw 24 of FIG. 18 would extend well outwardly of the pawl and might interfere with operation of the wrench. In the embodiment of FIG. 32 the region I14 of jaw 108 has a reduced radius to obviate this problem.

An advantage is achieved with this embodiment in that since ratcheting occurs at only 60 intervals the pawl surfaces are not required to be rotated during inward and outward movement of the pawl. The pawl may travel a straight path thereby eliminating the necessity for arcuate surfaces on the pawl and adjacent surfaces of the wrench thereby reducing the cost of the unit. The reason for this feature is discussed in greater detail subsequently.

Where ratcheting occurs at 30 intervals as in the prior embodiments of the invention the nut must rotate relative to the jaws during the ratcheting intervals since the nut engages different surfaces of the jaws at each 30 increment. However where only 60 ratcheting is contemplated, the rotation of the nuts of different sizes is quite minimal and as a practical matter may be disregarded completely. Therefore it is not necessary to utilize a pawl which rotates relative to the remainder of the wrench and a pawl having a straight-line surface engaging the main body of the wrench may be utilized. This approach does introduce some drag between the pawl and the main body of the wrench during ratcheting but as is indicated subsequently this drag is not great and may be reduced to unimportant levels.

Referring now specifically to FIG. 32 of the accompanying drawings, there is illustrated a wrench generally designated by the reference numeral I06 having a wrench handle I07 and a lower jaw generally designated by the reference numeral 108. Since 60 ratcheting is employed, only the nut engaging surfaces 4 and 13 on the main body of the wrench and the surface [8 on the pawl need be provided. Material may be removed from the jaw I08 in the regions where the other engaging surface existed in the prior embodiments. Pawl I09 may employ the slide or yoke forms illustrated in FIG. 18 and FIG. 24, respectively, and in the embodiment illustrated in FIG. 32 takes the yoke form of the embodiment of FIG. 24. Thus the pawl I09 constitutes a pair of arms, only one of which is illustrated, the finger III. The mating surfaces of the pawl 109 and the end region of the main body of the wrench are in other respects identical with that illustrated in FIGS. 28 and 29. The finger 111 is received in a slot 112 formed in the jaw I08 of the wrench and is biased inwardly by a pull rod 113 connected to a compression spring, not illustrated, in a manner previously described.

It is apparent that the finger 111 of the pawl I09 and the corresponding member on the other side which is not illustrated do not follow a precise linear motion relative to the surfaces of the main body of the wrench and thus during ratcheting there is an outward force on the pawl due to rotation relative to the nut, and there is some disengagement of the member Ill from the mating surfaces of the main body of the wrench. Specifically the pawl tends to be rotated somewhat counterclockwise as viewed in FIG. I during a ratcheting operation. Some drag does develop at the tail of the member III as a result of this rotation of the pawl but since during this period there is no appreciable load on the surfaces the drag instituted is small particularly if the width of the slot H2 is somewhat wider than the corresponding width of the finger III thus permitting a slight canting of the member III in the slot. About a 10 percent additional width of the slot 112 relative to the member III has been found sufficient to prevent undue binding of the relative parts during a ratcheting operation. During a tightening operation any binding which may result is helpful in holding the pawl in place.

There is an additional modification of the wrench of FIG. 32 relative to that illustrated in prior figures. Upper surface 114 as viewed in FIG. 32 of the short jaw of the wrench has a smaller radius of curvature than the corresponding surfaces of the wrench of the prior embodiments. The reason for this is that with a large range of nuts which this embodiment of the wrench is intended to accommodate, where working with smaller nuts the outer jaw must be cut back so that it does not stick out to an appreciable extent beyond the wrench and interfere with surrounding materials or members. There is some sacrifice of strength as a result of this cut back in the surface 114 but the loss is quite small and the overall result is considered advantageous in view of the results achieved.

Referring now specifically to FIG. 33 of the accompanying drawings, there is illustrated a closed-end wrench generally designated by the reference numeral I16 utilizing a pawl 117 which slides along a straight line, as does the pawl of FIG. 32, in a slot I18 formed in the handle of the wrench. The pawl is biased inwardly towards the jaw and its innermost position is indicated by reference numeral "7' and its fully retracted position by reference numeral H7". The pawl provides a single nut engaging surface I8 which together with surfaces 4 and I3 of the fixed jaw of the wrench provide three points of contact between the wrench and the nut to be driven thereby.

The operation of the wrench of FIG. 33 so far as the sliding of the pawl is concerned is the same as in FIG. 32 and the configuration so far as the closed end wrench is concerned, conforms to that of the embodiment of FIG. hereof. One change relative to FIG. 30 however should be noted. During the ratcheting motion the pawl 117 is pressed against the lower surface as viewed in FIG. 33 of the slot 118 in which the pawl is located. in order to reduce binding that might occur during ratcheting, the mating grooves and projections of FIG. 31 are removed from the lower mating surfaces so that smooth sliding surfaces are in contact, providing a low coefficient of friction and thus little tendency to bind. Again in this embodiment of the invention a certain amount of play is allowed in the movement of the pawl perpendicular to the major elongated dimension of the wrench so as to reduce binding during ratchet- Referring now specifically to FIG. 34 of the accompanying drawings there is illustrated a box end wrench that also only ratchets at the 60 positions. The embodiment also employs a straight slide but differs from the embodiment of FIG. 33 in that the length along the elongated dimension of the wrench, of the end part of the jaw is smaller than in the prior Figure. In this embodiment only two nut engaging surfaces are provided, one on the pawl and one on the jaw of the wrench, designated by reference numeral 119. In consequence of providing only a single nut engaging surface on the main body of the wrench the region of the wrench designated by reference numeral 119 is not required to be as long as in FIG. 33.

As indicated, only two nut engaging surfaces are provided, a surface 121 on the fixed part of the wrench and a surface 122 on pawl 123. The surfaces 121 and 122 are parallel as in conventional wrenches, The pawl is provided with an extension 124 extending downward in FIG. 34 and is provided with a further leftward angled projection 126 from the extension 124. The surface 126 although it engages the nut does not provide a driving surface but prevents the nut from slipping during ratcheting operations.

In order to accommodate the extensions 124 and 126, the main body of the wrench is recessed at 127 so that the pawl may move without impediment between its maximum and minimum extended positions.

While I have described and illustrated specific embodiments of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

I claim:

1. A ratcheting end wrench having a handle terminating at at least one end in a nut engaging jaw member,

said jaw member having interior surfaces defining nut engaging surfaces,

a pawl having a generally arcuate body member and an elongated body member including an arcuate end surface adjacent said arcuate body member generally transverse to the elongated dimension of said elongated body member, said elongated body member defining nut engaging surfaces in opposition to said nut engaging surfaces of said jaw memher,

said wrench having at least one generally arcuate re cess opening into the interior of said jaw member, and having approximately the same curvature as said arcuate body member of said pawl.

means for retaining said arcuate body member in sliding contact within said at least one arcuate recess in said wrench for movement within said arcuate recess between innermost and outermost nut engaging positions,

means biasing said pawl towards its innermost nut engaging position.

the center of curvature of said generally arcuate recess lying approximately along the perpendicular bisector of a line defined by the path of movement between innermost and outermost nut engaging positions of a nut engaging region of said pawl,

said center of curvature lying at a distance from said line equal to approximately 3 to 4 times the distance from the center to a flat surface of a nut to be engaged by said wrench.

2. The invention according to claim I wherein said jaw member terminates in an arcuate end surface re mote from said jaw engaging surfaces thereof and adja cent to and in contact with said arcuate end surface of said pawl and including means for providing an effective coefficient of friction between said arcuate end arcuate surface of said elongated body member and said arcuate surface of said jaw member such that the center of curvature of said arcuate end surface of said elongated body member lies on the jaw member side of the normal force vector between said arcuate surface of said jaw member and said arcuate end arcuate surface of said elongated body member.

3. The invention according to claim 2 wherein said means for providing includes a tongue formed on and defining one surface of said arcuate end surface of said elongated body member and a groove formed in and defining said arcuate end surface of said jaw member, the angle (8) lying in a plane transverse of said groove and defined by one of the surfaces defining a side of said groove and the bottom surface of said groove being determined by the formula 5 arc csc L where a is the desired coefficient of friction and a is the coefficient of friction between the materials of said arcuate surfaces.

4. The invention according to claim 3 further comprising interleaved members lying between said tongue and groove members whereby to increase the friction therebetween.

5. The invention according to claim 2 wherein said means for providing comprises interleave members lying between and each secured to move with the arcuate surface remote therefrom.

6. The invention according to claim 2 wherein said center of said arcuate recess and arcuate body member has a projection on the axis of said jaw member lying outward of the end of said jaw member.

7. The invention according to claim 1 further com prising means for moving said pawl toward its outermost position, said means including a channel in said handle,

a rod positioned in said channel along the major axis thereof,

means causing said pawl to move toward said outermost position in response to movement of said rod,

means for biasing said rod to move said pawl towards its innermost position, and

means for pushing said rod to cause said pawl to move towards its outermost position.

8. A ratcheting end wrench having a handle terminating at at least one end in a generally U-shaped jaw member having a base and two legs wherein one of said legs is longer than the other of said legs,

said one leg and said base of said U-shaped member having an interior surface defining a plurality of nut-engaging surfaces,

said other leg terminating in an arcuate surface lying generally transverse to the axis of said legs,

a movable pawl having an arcuate surface with approximately the same radius of curvature as the arcuate surface of said other leg and an interior surface generally transverse to said arcuate surfaces and defining nut engaging surfaces,

means for retaining said pawl on said wrench with its arcuate surface in engagement with said arcuate surface of said other leg and for causing movement along said arcuate surface of said other leg between innermost and outermost nut engaging positions,

means for biasing said pawl towards its innermost nut engaging position,

the center of curvature of said arcuate surfaces lying generally along the perpendicular bisector of an are extending between the innermost and outermost nut engaging positions of a nut engaging region of the nut engaging surface of said pawl,

said center of curvature lying at a distance from said nut engaging region on said nut engaging surface of said pawl equal to approximately 3 to 4 times the distance from the center to a flat surface of a nut to be engaged by said wrench,

9. The invention according to claim 8 wherein said center of curvature of said arcuate surfaces has a projection on an axis of said U-shaped member lying generally equidistant between said legs, said projection lying outward of the end of said one leg.

10. The invention according to claim 9 wherein said means causing said pawl to move comprises a recess in and generally transverse to said handle adjacent said U-shaped member,

a slide member extending from said pawl into said recess and having a radius of curvature with the same center of curvature as said arcuate surfaces, a rod lying in a recess in said handle, means for pushing on said rod. and means for coupling movement of said rod to said slide member.

11. The invention according to claim wherein said last mentioned means comprises a rotatable sector gear having said rod connected thereto and a mating sector gear formed on said slide.

12. The invention according to claim 10 wherein said axis of said U-shaped member lies at an angle of about l5-2t) relative to the axis of said handle and wherein said passage in said handle provides a smooth, generally continuous curve from said means for pushing to said slide member, said rod being connected to said slide member.

13. A ratcheting end wrench having a handle terminating at at least one end in a generally U-shaped jaw member having a base and two legs wherein one of said legs is longer than the other leg,

said one leg and said base of said U-shaped member having an interior surface defining a plurality of not-engaging surfaces,

said other leg terminating in an arcuate surface lying generally transverse to the axis of said legs,

a movable pawl having an arcuate surface with approximately the same radius of curvature as the arcuate surface of said other leg and an interior surface defined by nut engaging surfaces.

means for supporting said pawl on said wrench with its arcuate surface in engagement with said arcuate surface of said other leg and for movement along said arcuate surface of said other leg between innermost and outermost nut engaging positions,

the center of said arcuate surfaces lying generally along the perpendicular bisector of an arc extending between the innermost and outermost nut engaging positions of said pawl,

said center of curvature having a projection on the axis of said U-shaped jaw member lying outward of the end of said one leg and lying on the U-shaped jaw member side of the force vector between said arcuate surfaces when tightening a screw-like device.

14. A jaw for an open-end ratcheting wrench comprising a generally U-shaped jaw member having a long leg, a short leg and a base and having at least 9 surfaces formed on the interior surfaces of said long leg and said base and defined nominally in accordance with the nut engaging surfaces of a 12 point socket wrench, and a first of said surfaces lying adjacent the end of said long leg of said U-shaped jaw member and the 4th, 5th, and 7th of the surfaces of a 12 point socket configuration being relieved sufficiently to accommodate a screw device polygonal head which is at least 8 percent less in size than the maximum size for which said jaw is designed.

15. The invention according to claim 14 wherein the 4th, 5th, 6th, and 7th surfaces ofa 12 point socket eonfiguration are removed completely to define a generally smooth continuous surface.

16. An adjustable ratcheting end wrench comprising a handle terminating at at least one end in a head defining a fixed jaw member,

said jaw member having an interior nut-engaging surface,

a pawl having an elongated body member and a generally transverse nut engaging surface,

at least one recess formed in said head to receive said elongated body of said pawl,

said recess opening into an interior region of said head defined in part by said nut-engaging surface of said member jaw,

said body of said pawl positioned in said recess,

means for resiliently urging said pawl into said interior region of said head,

said recess defining a path of movement of said pawl such that said pawl is pressed against a surface of said head during a driving rotation of said wrench and is translated generally parallel to the axis of 

1. A ratcheting end wrench having a handle terminating at at least one end in a nut engaging jaw member, said jaw member having interior surfaces defining nut engaging surfaces, a pawl having a generally arcuate body member and an elongated body member including an arcuate end surface adjacent said arcuate body member generally transveRse to the elongated dimension of said elongated body member, said elongated body member defining nut engaging surfaces in opposition to said nut engaging surfaces of said jaw member, said wrench having at least one generally arcuate recess opening into the interior of said jaw member, and having approximately the same curvature as said arcuate body member of said pawl, means for retaining said arcuate body member in sliding contact within said at least one arcuate recess in said wrench for movement within said arcuate recess between innermost and outermost nut engaging positions, means biasing said pawl towards its innermost nut engaging position, the center of curvature of said generally arcuate recess lying approximately along the perpendicular bisector of a line defined by the path of movement between innermost and outermost nut engaging positions of a nut engaging region of said pawl, said center of curvature lying at a distance from said line equal to approximately 3 to 4 times the distance from the center to a flat surface of a nut to be engaged by said wrench.
 2. The invention according to claim 1 wherein said jaw member terminates in an arcuate end surface remote from said jaw engaging surfaces thereof and adjacent to and in contact with said arcuate end surface of said pawl and including means for providing an effective coefficient of friction between said arcuate end arcuate surface of said elongated body member and said arcuate surface of said jaw member such that the center of curvature of said arcuate end surface of said elongated body member lies on the jaw member side of the normal force vector between said arcuate surface of said jaw member and said arcuate end arcuate surface of said elongated body member.
 3. The invention according to claim 2 wherein said means for providing includes a tongue formed on and defining one surface of said arcuate end surface of said elongated body member and a groove formed in and defining said arcuate end surface of said jaw member, the angle ( delta ) lying in a plane transverse of said groove and defined by one of the surfaces defining a side of said groove and the bottom surface of said groove being determined by the formula
 4. The invention according to claim 3 further comprising interleaved members lying between said tongue and groove members whereby to increase the friction therebetween.
 5. The invention according to claim 2 wherein said means for providing comprises interleave members lying between and each secured to move with the arcuate surface remote therefrom.
 6. The invention according to claim 2 wherein said center of said arcuate recess and arcuate body member has a projection on the axis of said jaw member lying outward of the end of said jaw member.
 7. The invention according to claim 1 further comprising means for moving said pawl toward its outermost position, said means including a channel in said handle, a rod positioned in said channel along the major axis thereof, means causing said pawl to move toward said outermost position in response to movement of said rod, means for biasing said rod to move said pawl towards its innermost position, and means for pushing said rod to cause said pawl to move towards its outermost position.
 8. A ratcheting end wrench having a handle terminating at at least one end in a generally U-shaped jaw member having a base and two legs wherein one of said legs is longer than the other of said legs, said one leg and said base of said U-shaped member having an interior surface defining a plurality of nut-engaging surfaces, said other leg terminating in an arcuate surface lying generally transverse to the axis of said legs, a movablE pawl having an arcuate surface with approximately the same radius of curvature as the arcuate surface of said other leg and an interior surface generally transverse to said arcuate surfaces and defining nut engaging surfaces, means for retaining said pawl on said wrench with its arcuate surface in engagement with said arcuate surface of said other leg and for causing movement along said arcuate surface of said other leg between innermost and outermost nut engaging positions, means for biasing said pawl towards its innermost nut engaging position, the center of curvature of said arcuate surfaces lying generally along the perpendicular bisector of an arc extending between the innermost and outermost nut engaging positions of a nut engaging region of the nut engaging surface of said pawl, said center of curvature lying at a distance from said nut engaging region on said nut engaging surface of said pawl equal to approximately 3 to 4 times the distance from the center to a flat surface of a nut to be engaged by said wrench.
 9. The invention according to claim 8 wherein said center of curvature of said arcuate surfaces has a projection on an axis of said U-shaped member lying generally equidistant between said legs, said projection lying outward of the end of said one leg.
 10. The invention according to claim 9 wherein said means causing said pawl to move comprises a recess in and generally transverse to said handle adjacent said U-shaped member, a slide member extending from said pawl into said recess and having a radius of curvature with the same center of curvature as said arcuate surfaces, a rod lying in a recess in said handle, means for pushing on said rod, and means for coupling movement of said rod to said slide member.
 11. The invention according to claim 10 wherein said last mentioned means comprises a rotatable sector gear having said rod connected thereto and a mating sector gear formed on said slide.
 12. The invention according to claim 10 wherein said axis of said U-shaped member lies at an angle of about 15*-20* relative to the axis of said handle and wherein said passage in said handle provides a smooth, generally continuous curve from said means for pushing to said slide member, said rod being connected to said slide member.
 13. A ratcheting end wrench having a handle terminating at at least one end in a generally U-shaped jaw member having a base and two legs wherein one of said legs is longer than the other leg, said one leg and said base of said U-shaped member having an interior surface defining a plurality of not-engaging surfaces, said other leg terminating in an arcuate surface lying generally transverse to the axis of said legs, a movable pawl having an arcuate surface with approximately the same radius of curvature as the arcuate surface of said other leg and an interior surface defined by nut engaging surfaces, means for supporting said pawl on said wrench with its arcuate surface in engagement with said arcuate surface of said other leg and for movement along said arcuate surface of said other leg between innermost and outermost nut engaging positions, the center of said arcuate surfaces lying generally along the perpendicular bisector of an arc extending between the innermost and outermost nut engaging positions of said pawl, said center of curvature having a projection on the axis of said U-shaped jaw member lying outward of the end of said one leg and lying on the U-shaped jaw member side of the force vector between said arcuate surfaces when tightening a screw-like device.
 14. A jaw for an open-end ratcheting wrench comprising a generally U-shaped jaw member having a long leg, a short leg and a base and having at least 9 surfaces formed on the interior surfaces of said long leg and said base and defined nominally in accordance with the nut engaging surfaces of a 12 point socket wrench, and a first of said surfaces lying adjacent tHe end of said long leg of said U-shaped jaw member and the 4th, 5th, and 7th of the surfaces of a 12 point socket configuration being relieved sufficiently to accommodate a screw device polygonal head which is at least 8 percent less in size than the maximum size for which said jaw is designed.
 15. The invention according to claim 14 wherein the 4th, 5th, 6th, and 7th surfaces of a 12 point socket configuration are removed completely to define a generally smooth continuous surface.
 16. An adjustable ratcheting end wrench comprising a handle terminating at at least one end in a head defining a fixed jaw member, said jaw member having an interior nut-engaging surface, a pawl having an elongated body member and a generally transverse nut engaging surface, at least one recess formed in said head to receive said elongated body of said pawl, said recess opening into an interior region of said head defined in part by said nut-engaging surface of said member jaw, said body of said pawl positioned in said recess, means for resiliently urging said pawl into said interior region of said head, said recess defining a path of movement of said pawl such that said pawl is pressed against a surface of said head during a driving rotation of said wrench and is translated generally parallel to the axis of said recess during ratcheting rotation of said wrench, means for increasing the normal coefficient of friction between said pawl body and said surface of said head of said wrench, said nut-engaging surface of said pawl lying at such an angle to said pawl body as to engage a flat surface of a nut to be rotated by said wrench concurrently with engagement of a generally opposed surface of the nut by said nut-engaging surface of said fixed jaw member, said path defined by said recess maintaining said nut-engaging surface of said pawl generally parallel to an adjacent surface of a nut over the range of nut sizes for which said wrench is designed.
 17. The invention according to claim 16 wherein said fixed jaw member defines two nut-engaging surfaces.
 18. The invention according to claim 16 wherein the path of engagement between engaging edge surfaces of said pawl body and said recess is an arcuate path, the center of curvature of said arcuate path lying generally along a perpendicular bisector of an arc extending between the innermost and outermost nut engaging positions of a nut engaging region on the nut-engaging surface of said pawl, said center of curvature lying at a distance from said predetermined location on said nut engaging surface of approximately 3 to 4 times the distance from the center to a flat surface of a nut to be engaged by said wrench.
 19. The invention according to claim 16 wherein said jaw member comprises a generally U-shaped jaw member having a long leg, a short leg and base and having at least 9 surfaces formed on the interior surfaces of said long leg and said base defined nominally in accordance with a 12 point socket wrench, a first of said surfaces lying adjacent the end of said long leg of said U-shaped jaw member, the 4th, 5th, and 7th of the surfaces of a 12 point socket configuration being relieved sufficiently to accommodate a screw device polygonal head which is at least 8 percent less in size than the maximum size for which said jaw is designed.
 20. The invention according to claim 16 wherein said nut-engaging surfaces of said fixed jaw member and said pawl are substantially parallel and wherein said pawl member has a second nut-engaging surface contacting a nut to be driven by said wrench at a location forward of the location of the first mentioned nut-engaging surface during driving rotation of the nut.
 21. The invention according to claim 18 wherein said nut-engaging surfaces of said fixed jaw member and said pawl are substantially parallel and wherein said pawl Member has a second nut-engaging surface contacting a nut to be driven by said wrench at a location forward of the location of the first mentioned nut-engaging surface during driving rotation of the nut, said nut engaging region comprising said second nut engaging surface.
 22. The invention according to claim 8 wherein said nut-engaging surfaces of said fixed jaw member and said pawl are substantially parallel and wherein said pawl member has a second nut-engaging surface contacting a corner of a nut to be driven by said wrench at a location forward of the location of the first mentioned nut-engaging surface during driving rotation of the nut.
 23. A ratcheting end wrench having a handle terminating at at least one end in a nut engaging jaw member, said jaw member having interior surfaces defining nut engaging surfaces, a pawl comprising an elongated body member defining nut engaging surfaces and a slide member, a recess in said handle for receiving said slide member, said nut engaging surfaces of said pawl being opposed to said nut engaging surfaces of said jaw member, means for biasing said pawl toward said jaw member, a slot formed in said handle, a rod located in said slot for sliding movement therein, means for biasing said rod toward said jaw member, means for moving said rod away from said jaw member, and means coupling said rod and said pawl.
 24. The invention according to claim 23 wherein said slide and said recess are generally arcuate and extend generally transverse of said handle of said wrench, said recess extends into said jaw member from said handle, and wherein said rod is flexible and is connected to said slide in a region of said recess in said jaw member.
 25. The invention according to claim 23 wherein said slide and said recess are generally arcuate and extend generally transverse of said handle of said wrench, said recess extending into said jaw member, said nut engaging surfaces of said jaw member and said pawl defining two distinct groups of nut engaging surfaces, a first of said groups engaging flat surfaces of a nut, a second of said groups engaging a corner of a nut, the center of curvature of said arcuate slide and arcuate recess lying along the perpendicular bisector of a line defined by the path of movement of the nut engaging surface of said pawl of said second group of said nut engaging surfaces.
 26. The invention according to claim 23 wherein said wrench is a closed-end wrench, and wherein said slide and said recess are arcuate and wherein said nut engaging surfaces of said jaw member and said pawl define two distinct groups of nut engaging surfaces, a first of said groups engaging flat surfaces of a nut, a second of said groups engaging a corner of a nut, the center of curvature of said arcuate slide and arcuate recess lying along the perpendicular bisector of a line defined by the path of movement of the nut engaging surface of said pawl of said second group of said nut engaging surfaces. 